This invention relates to a lifting device for a palletized load, and more particularly to a lifting device having a rigid lifting frame received within openings of a pallet and supported from flexible cables.
Heretofore, various lifting devices for palletized loads have been provided in which a crane is effective to lift the palletized load by cables connected to the lifting device. For example, U.S. Pat. No. 4,550,940 shows a lift mechanism which includes a pair of separate lift units connected to the pallet. Each lift unit must be separately connected to the pallet. Such an arrangement requires a relatively complex connection to the pallet and is time consuming.
Loaded pallets are lifted and transported from one area or location to another such as when loading or unloading ships, flatbed trucks, or trains. When loading or unloading pallets from ships, the ship may be rolling or pitching due to various sea conditions and it is necessary that a safe transfer of the palletized load be made. Palletized loads are often stacked vertically on ships or the like, and a lifting device should be easily connected to an upper stacked palletized load for lifting and transfer to another location or area.
A pallet normally has lower stringers mounted between upper planking and lower planking to define an opening between the upper planking which supports the load and the lower planking which is mounted on a supporting surface. A lifting device normally has lift members received within the opening of the pallet between the upper and lower planking for contacting and lifting of the pallet.
It is desired that a lifting device for palletized loads be provided that is easily connected to the palletized load for lifting in a relatively simple manner in a minimum of time.
The present invention includes a rigid lower L-shaped lifting frame connected to a plurality of support cables for lifting of the palletized load. The rigid L-shaped lifting frame has a pair of lower parallel lift legs which fit in openings in the pallet and a back for fitting against a side of a pallet or palletized load. The free ends of the legs opposite the back extend through the pallet openings and outwardly of the pallet. Lift cables are connected to the back and to the free ends of the legs. The cables connected to the free ends of the legs are manually released or unhooked from the legs prior to insertion of the legs within the openings of the pallet. After the legs are inserted within the openings, the cables are reconnected to the legs for lifting of the palletized load.
The rigid L-shaped lifting frame is a rigid one-piece integral frame and when the cables are unhooked from the free end of the legs, the frame tilts at an angle from the rear support cables connected to the back of the lifting frame. The legs of the tilted frame are particularly easy to insert within openings in upper vertically stacked loaded pallets.
Another feature of the invention is the provision of a floating spreader ring connected to the four cables for maintaining the cables in spaced relation to each other without twisting of the cables when the lifting frame is unloaded. The spreader ring may move along the cables for maintaining the cables in a straight direction from the lifting frame to the lift ring at the upper ends of the cables.
It is an object of the invention to provide a lifting device for a palletized load which is easily connected to the palletized load for lifting in a minimum of time.
It is a further object of the invention to provide such a lifting device including a one-piece rigid L-shaped lifting frame supported by cables connected to the one-piece rigid lifting frame.
An additional object is to provide such an L-shaped rigid lifting frame having cables releasably connected to the free ends of the lower lifting legs with the cables being released from the free ends of the legs for insertion of the legs within openings of a pallet, and then reattached to the legs for lifting of the pallet.
A still further object is the provision of a rigid lifting frame supported from four cables and having a spacer ring to maintain spacing of the cables and to minimize twisting of the cables and lifting frame in an unloaded condition.
It is still another object of the invention to provide a lifting device with a minimum of operating parts required, is inexpensive to manufacture, and is easily attached to a palletized load for lifting.